Field of the Invention
The present invention relates to an apparatus for removing the catalyst surface substances from a catalyst.
Description of the Related Art
The fluidized bed reaction is applied to a wide variety of reactions because the fluidized bed reaction has such a satisfactory handleability that the catalyst involved can be extracted and replenished even during operation and moreover, the temperature gradient inside the reactor is smaller and the heat removal efficiency is higher as compared to the fixed bed. For example, an intended nitrile has been produced by ammoxidation of an alkene with a fluidized bed reactor, and for the purpose of making the fluidized bed reaction efficiently proceed, various reaction conditions in the fluidized bed reaction have also been investigated.
On the other hand, the physical properties known to be required for the catalyst in the fluidized bed reaction include the high fluidity and the high abrasion resistance. Japanese Patent Laid-Open No. 2007-216212 describes the fact that when exuded substances and/or attached substances are present on the surface of a catalyst, the fluidity is impaired, and also the fact that when the exuded substances and/or the attached substances are present in an amount of 2 wt % or more based on the mass of the catalyst, the fluidity is degraded and the reaction is not stabilized.